Abstract
Abstract—Traffic congestion is a global problem affecting most countries in the world, especially developed countries. It wastes time and energy. In Libya, the current traffic light system works with static time and fixed cycle length. Due to these most of traffic junctions are busy. To solve such traffic congestion smart or intelligent traffic light system with a varying green time and cycle length depending on traffic density is proposed in this paper. This intelligent traffic system is based on programmable logic controller (PLC), and Supervisory Control and Data Acquisition (SCADA).In this system, the traffic density data are collected by detectors or cameras located at each traffic signal and then transmitted to the PLC. The overall traffic processes are controlled and supervised by SCADA system. The flow of traffic at different junctions in Alfornaj region in Tripoli is taken as case study. The results obtained are remarkably good, where green time and cycle length are controlled and delay time of each vehicle at traffic junction is minimized.